In the art, it is generally known that warm or contaminated air is generated in the housings of the most varied devices, which air has to be removed. For example, in particular warm air must be removed in order to prevent overheating of the individual components inside the housing. In printing machines ozone, for example, can be generated or it is also possible for fine toner particles to be in the air, which should be ventilated. Consequently, it is necessary to provide appropriate ventilation of the housing.
In the art, the most varied ventilating devices are known, usually, e.g., printing machines comprise a blower in order to conduct air from the inside of the device housing directly to the outside into the immediate environment. However, in doing so, the potentially warm or contaminated air moves into the immediate environment of the device, this being potentially unpleasant for an operator of the device.
Therefore, it is also known to provide so-called support ventilators outside the device housing. Usually, support ventilators comprise a second blower and an ascending pipe in order to convey air exhausted from the device housing even farther, preferably out of the room in which the device is set up. The second blower, as a rule, is necessary because the device blower, as a rule, is not capable of conveying the air through the ascending pipe.
In the arrangement described above, a flow chamber is usually provided between the device blower and the blower of the support ventilator, said flow chamber being sealed with respect to the environment and consisting, for example, of only a tube. However, such an arrangement presents the problem that, for example, the device ventilator would no longer be able to convey air out of the device housing when the blower of the support ventilator fails. This could result in an overheating of individual components or in an unacceptable increase of the contamination level inside the device housing. In order to avoid such a situation, it is known to provide an electronic control that continually monitors the individual components and, for example, provides an emergency shut-off for the device in case of a malfunction of the support ventilator blower. If, however, the device blower would to fail but the blower of the support ventilator would continued to be operated, the blower of the support ventilator would continue to take in air—even though at a smaller volume—from the device housing, because the support of the device blower would be missing. This may result in inadequate ventilation and lead to the previously mentioned problems. In addition, the intake of air through the support ventilator blower could cause the device blower to move, this potentially resulting in further damage. In addition, the blower of the support ventilator, because it is now no longer supported by the device blower, could easily overheat and also be damaged. Consequently, an appropriate electronic control would also trigger an emergency shut-off of the device in such a case. However, as a rule, an emergency shut-off of a device is not desirable because this could lead to even more problems.